What water quality conditions should be considered when mixing Clostridium

      When mixed with other probiotics such as Bacillus, lactic acid bacteria, photosynthetic bacteria, etc., the water quality conditions will directly affect the activity, metabolic efficiency, and synergistic effect of each strain. Key attention should be paid to the following core water quality parameters, taking into account the physiological needs of different bacterial strains, and avoiding "functional conflicts" or "activity inhibition" caused by environmental discomfort:

1、 Dissolved oxygen (DO): Balancing the "survival balance" of aerobic and anaerobic bacteria

      Clostridium butyricum is a strictly anaerobic bacterium that exhibits optimal activity in environments with dissolved oxygen levels below 0.5 mg/L, such as intestinal mucosa and pond bottoms; Most of the probiotics used in combination, such as Bacillus and yeast, are aerobic/facultative anaerobic bacteria that require dissolved oxygen levels greater than 2 mg/L for efficient reproduction (decomposition of residual feed, oxygen consumption for antibacterial purposes). When mixed, it is necessary to achieve "layered adaptation" through water quality control:

      Overall dissolved oxygen in water: It is recommended to maintain it at 3-5 mg/L (for fish) or 4-6 mg/L (for shrimp and crab). At this point, aerobic bacteria can exert their effects in the upper layer of the water (high dissolved oxygen zone), while Clostridium butyricum can colonize in the lower layer (low dissolved oxygen, usually 1-2 mg/L lower than the surface layer) and intestinal tract. The two are spatially separated to reduce competition.

      Avoid sudden drops in dissolved oxygen: If a large amount of aerobic bacteria (such as Bacillus) are mixed, be alert to the oxygen consumption characteristics that may cause a sudden drop in dissolved oxygen (especially in organic rich water bodies). When the dissolved oxygen is less than 2 mg/L, the activity of aerobic bacteria is inhibited, and it may trigger a large proliferation of bottom anaerobic microorganisms (such as sulfate reducing bacteria), producing hydrogen sulfide (H ₂ S), which in turn inhibits butyric acid bacteria (sensitive to H ₂ S).

      Regulation method: Factory farming can maintain bottom dissolved oxygen through oxygenation equipment (such as bottom oxygenation); Soil ponds can reduce the single dose of aerobic bacteria (recommended ≤ 500 g/mu · m), or be used in different time periods (spraying aerobic bacteria during the peak oxygen increase period from 9-10 am, and spraying Butyricinetobacter in the evening).

2、 PH value: Avoid dual inhibition of "high acidity" or "strong alkalinity"

      Different probiotics have different pH tolerance ranges, and mixed use should be maintained within the "cross appropriate range":

      Clostridium butyricum: has a wide tolerance range (pH 4.0~7.5), with an optimal pH of 5.5~6.5 (slightly acidic).

      Aerobic bacteria (such as Bacillus): The optimal pH is 7.0-8.0 (neutral to alkaline), and their activity significantly decreases when pH<6.0.

      Lactic acid bacteria: Lactic acid production can lower the environmental pH, with a self tolerance of pH 3.0~6.0, but excessive production can lead to water pH<6.0, inhibiting Bacillus subtilis.

      Suggested control range: Maintain the pH of the water at 6.5-8.0 (for fish) or 7.0-8.5 (for shrimp and crab). If mixed with lactic acid bacteria, pH changes need to be monitored. When the pH is less than 6.5, reduce the amount of lactic acid bacteria used (or adjust with a small amount of quicklime, using 5-10 kg per acre/meter to avoid sudden pH rise); If the pH is greater than 8.5 (such as during the blue-green algae bloom period), organic acids (such as citric acid, 1-2 kg/mu · m) can be sprinkled first to lower the pH before use, to avoid excessive alkalinity that inhibits Butyricinetobacter.

3、 Ammonia nitrogen (NH ∝ - N) and nitrite (NO ₂⁻ - N): controlling the "toxicity threshold"

      High concentrations of ammonia nitrogen (especially molecular ammonia NH3) and nitrite are toxic to most probiotics, disrupting cell membrane permeability and inhibiting metabolic enzyme activity

      Safety threshold: Ammonia nitrogen<0.5 mg/L (molecular ammonia<0.02 mg/L), nitrite<0.3 mg/L (freshwater) or<0.1 mg/L (seawater).

      Why is it important? Although Clostridium butyricum can indirectly reduce ammonia nitrogen by decomposing nitrogen-containing organic compounds, it cannot directly degrade nitrite; Bacillus and photosynthetic bacteria can degrade ammonia nitrogen and nitrite, but their own activity is inhibited at high concentrations. If the water quality exceeds the standard, the mixed probiotics not only have poor effects, but may also cause "secondary pollution" (organic matter released by bacterial decomposition) due to bacterial death.

      Pre treatment: When exceeding the standard, change the water by 1/3~1/2 or sprinkle zeolite powder (20-30 kg/mu · m) for adsorption. Wait until the indicator drops to the safe range before using probiotics.

4、 Water temperature: matching the "metabolic activity window" of bacterial strains

      Temperature directly affects the reproduction rate and enzyme activity of probiotics. When mixed, it is necessary to ensure that the water temperature is within the "appropriate overlapping zone" of each strain:

      Clostridium butyricum: The optimal water temperature is 25-37 ℃ (its activity drops sharply when the water temperature is below 15 ℃, and it is prone to deactivation when the water temperature is above 40 ℃).

      Bacillus: The most suitable temperature is 20-30 ℃ (water temperature<10 ℃ almost does not reproduce).

      Lactic acid bacteria: most suitable for 30-37 ℃ (stable activity at low temperatures, but slow reproduction).

      Photosynthetic bacteria: most suitable for 25-32 ℃ (requires light synergy, low efficiency at low temperatures).

      Suggested water temperature: maintain at 20~32 ℃. Low temperature seasons (such as early spring and late autumn) can reduce the amount of aerobic bacteria used (slow metabolism), and prioritize the use of Clostridium butyricum and lactic acid bacteria (slightly more tolerant to low temperatures); During the high temperature season (>35 ℃), it is necessary to avoid splashing at noon and choose early morning or evening to reduce bacterial heat damage.

5、 Organic Content (COD/Total Organic Matter): Provides nutrition but avoids "overload"

      Organic matter such as residual bait and feces in water bodies are sources of nutrients for probiotics, but excessive amounts can cause problems

      Suitable range: COD<15 mg/L (freshwater) or<20 mg/L (seawater), total organic matter<50 mg/L.

Risk points:

      Aerobic bacteria (such as Bacillus) require a large amount of oxygen to decompose organic matter. If there is an excess of organic matter (COD>20 mg/L), it can cause a sudden drop in dissolved oxygen and inhibit Clostridium butyricum.

      Anaerobic bacteria (such as Clostridium butyricum) may compete with spoilage bacteria (such as Escherichia coli) in high organic matter environments. If organic matter is not decomposed in a timely manner, it is easy to breed pathogenic bacteria.

      Regulation: When the organic matter exceeds the standard, aerobic bacteria (such as Bacillus) can be sprayed first to decompose for 2-3 days. After the COD drops to the appropriate range, butyric acid bacteria can be added (to avoid competing for dissolved oxygen at the same time).

6、 Light and Transparency: Special Requirements for "Photosynthetic Probiotics"

      If photosynthetic bacteria (which require light for photosynthesis) are mixed, attention should be paid to light intensity and water transparency:

      Light exposure: Photosynthetic bacteria require scattered light of 3000-10000 lux (avoid direct sunlight at noon, which can cause local heating). Insufficient light exposure can reduce their activity and affect the degradation efficiency of ammonia nitrogen.

      Transparency: It is recommended to have a transparency of 30-50 cm (i.e. "visibility" of 30-50 cm). If the transparency is too low (<20 cm, such as thick green water), it will block the light and inhibit photosynthetic bacteria; If the transparency is too high (>60 cm, such as lean water), there will be less algae, insufficient organic matter, and lack of nutrients for probiotics.

      Attention: Clostridium butyricum does not require light, and even avoiding light is more conducive to preservation. Therefore, when mixing photosynthetic bacteria, you can choose to sprinkle them in the morning when the light is suitable. Clostridium butyricum should be used in the evening or on cloudy days to avoid the potential impact of strong light on it (although not fatal, it may reduce its activity).

7、 Salinity: Suitable for "wide salinity" and "narrow salinity" strains

      The salinity difference between freshwater and seawater aquaculture is significant, and it is necessary to ensure that the mixed strains are adapted to the salinity of the aquaculture water:

      Freshwater aquaculture (salinity<0.5 ‰): Avoid using seawater specific strains (such as certain high salt tolerant Bacillus subtilis) and choose freshwater isolates (such as Bacillus subtilis freshwater type and Clostridium butyricum universal type).

      Marine aquaculture (salinity 25-35 ‰): Salt tolerant strains (such as Bacillus subtilis and salt tolerant lactic acid bacteria) need to be paired. Butyricibacter is mostly broad-spectrum (can adapt to salinity of 0-40 ‰), but the source of the strain needs to be confirmed (priority should be given to strains isolated from seawater environments).

      Sudden change in salinity: If the injection of fresh water during the rainy season causes a sudden drop in salinity (>5 ‰/day), the use of probiotics should be suspended and supplemented after the salinity stabilizes (salinity fluctuations can damage the osmotic pressure of bacterial cell membranes).

summary

      When using Clostridium butyricum in combination with other probiotics, the core of water quality regulation is "synergistic adaptation": by maintaining appropriate dissolved oxygen (layer balance), pH (cross zone), ammonia nitrogen/nitrite (safe threshold), taking into account the physiological needs of anaerobic bacteria (Clostridium butyricum), aerobic bacteria, and photosynthetic bacteria, while avoiding "stress factors" such as excessive organic matter and sudden changes in salinity. In practical operation, it is recommended to first test the water quality parameters, and then adjust them according to the aquaculture target (fish/shrimp/crab) and probiotic species. If necessary, use them at certain times (aerobic bacteria in the morning, anaerobic bacteria in the evening) to maximize the synergistic effect.